Question PC Freezing with graphics card - Replaced PSU, GPU, RAM, Clean install Windows, Updated BIOS

Jun 1, 2020

Thank you for any help you can provide. I built my PC in 2012, and it has worked flawlessly since then except for a RAM failure in 2014. It's my only desktop so it has been challenging to diagnose individual components. I've tried quite a few things so this will be a bit long.

MOBO: B75M-D3V (LGA 1155 socket)
CPU: i5-3470
RAM: 8GB DDR3 x2 (16gb total)
GPU: Nvidia GeForce 660 Ti
PSU: Corsair CX 600W bronze
HDD: 500gb Samsung SSD
OS: Windows 10 home - 64 bit

Last week when trying to load a new environment on a video game, the screen went black and it restarted. I logged back in, and it shut down again upon trying to initially populate the environment. I gave it 10 minutes and then able to load up the game, do a couple things, and then I exited the game 5 minutes later. The system event log only showed failed to create a file dump, kernel power cut, and unexpected shut down. So my diagnostic steps have been:

1. I ran windows diagnostic check, which found errors. I ran memtest86 and found out one of my RAM sticks was bad so I pulled it out. Now running on single stick 8gb of RAM. Booted to desktop fine, and then I turned it off. (3 shut offs for the day)

2. The next day I had a couple more shut offs and got BSOD NVLDDMKM Error twice (4 total for the day so far). I updated my graphics driver and ran DISM and SFC. The SFC found and corrected some corrupt files. No errors from DISM. I still got a couple more shut downs after with no graphics artifacting so I then ordered a new PSU. I figured it was likely the PSU because it is now 8 years old, and the freezes/restarts seemed random and not always related to graphics loading. However, I was able to run a video game for 6 consecutive hours without issue that night.

3. Day 3: More shut offs and lock ups mainly when trying to load a new environment in game but also random other times like opening Steam. Still able to play games but shut downs started happening more frequently (maybe 10 over the day) and started getting BSOD Video Scheduler Internal Error (maybe 4 times). So I stopped trying to play games on it.

4. Day 4: PC freezes more frequently at more random times like opening the start menu or 10 seconds after logging in. Or on start up, I get the BIOS screen, the Windows loading dots for a few seconds, and then the screen goes black. It ends up freezing during windows boot screen (with the white dots going in a circle before the login screen). I hard restart it, and I stopped getting video output at all. I tried switching to a vga cable through the onboard graphics and no luck either (video card was still in the PCIe slot). I reset the BIOS settings (unplugged PSU and took out CMOS battery), which did give me video again, but windows was now corrupted so I tried a system restore. During the normal restore process, it restarted, and I lost video again.

5. New PSU arrives (Corsair CX-M 450W) but still no video output through the GPU. I pulled out the video card at this point and used just the onboard graphics which worked, but windows still wouldn't start so I did a clean install. After getting a fresh Windows, I reinstalled the GPU, got video, but froze about 30 seconds after logging in. The PC was running fine without the graphics card in. I was able to load up a low-demanding game and run that with the onboard graphics. Additionally, the original PSU (600W) also worked fine. So I ordered a new graphics card.

6. Ran the Intel Processor Diagnostics Tool which found no errors. Ran Prime95 CPU stress test without errors. I also replaced the thermal paste on the CPU. Temperatures got up to 73C during Prime95 test.

7. New GPU (GTX 1650 Super) arrives. I drop it in, and I get the BIOS screen, the Windows loading dots for a few seconds, and then the screen goes black. I swapped in the old GPU (660 Ti) just to see what would happen, and I made it to the desktop and then it froze. I haven't been able to get any video output on the 1650S since first installing it. The 660 most often does the BIOS, dots, and then black.

8. Updated BIOS firmware (F6 to F13), but still no change in video output through the GPU on either the 1650S or 660.

9. Tried swapping out the RAM for an older 4gb DDR3 stick I had as a last ditch effort with no luck.

So now I'm guessing my motherboard is the issue--maybe the PCIe slot? Unfortunately, the mobo only has 1 PCIe x16 slot. The GPUs power on, fans run, and I can get video through them, but something is causing my system to lock up and freeze/restart when the GPU is in. I have swapped out the RAM, replaced the PSU, replaced the GPU, clean install windows, stress tested/diagnostic tool on CPU, reset BIOS settings, updated BIOS firmware. I'm not sure what else it can be at this point other than the mobo, but I'm hoping someone with more experience can guide me to find something else to test or confirm it is likely the mobo before I order a 3rd unnecessary part. Thank you so much for reading all of this and any help you can provide.